This invention relates to personal transportation devices and more specifically to scooters.
Most people walk at speeds of 3-6 kilometers per hour, so that walking a distance of 1 kilometer requires 10-20 minutes. For centuries, people have sought to increase the speed and/or the ease with which they travel.
Early transportation schemes employed watercraft (e.g., canoes, rafts) or large animals (e.g., camels, elephants, horses). Wheeled devices provided improved performance because of the ability of wheels to reduce the friction and associated energy dissipation in moving across the ground. In the early 1800s, two-wheeled human-powered devices called Draisines were invented and produced. A person using one of these devices straddled a frame and employed running for propulsion. In the mid-1800s, pedals were attached to Draisines creating the Velocipede, the precursor to the modern bicycle. Subsequent inventions include scooters, roller skates, and skateboards. Today, the dominant human-powered personal transportation devices include bicycles, roller skates, and skateboards. Scooters are also widely available.
Despite advances over the past several centuries, these existing devices fail to provide humans with efficient, highly convenient, small, lightweight, and easily deployed means of traveling distances of 10 km or less. Bicycles require substantial storage area, can not be easily carried in automobiles or on public transportation, and can be stolen when parked outdoors. Roller skates require substantial time to put on and take off, and when not in use are awkward to carry. Skateboards are small and light, but require substantial athletic ability to ride and can be frightening and dangerous when cornering or descending hills. Scooters, whether human-powered or motor-powered, have historically not been light enough or small enough to conveniently carry.
It is an object of this invention to provide a means of efficient personal transportation that can be easily carried and stored when not in use, and that is easily used by people with a wide range of athletic abilities.
A preferred embodiment of the invention is a scooter having a plurality of wheels, a steerer, a platform, and a steerer support. The steerer support connects the steerer to the platform. The steerer support can rotate with respect to the platform, allowing the scooter to be folded when not in use. The invention allows the steerer support to nest within the platform, further allowing the scooter to collapse into a compact position.
An aspect of the invention is also a configuration of the steering axis, front wheel diameter, and fork geometry that provides stable steering. Specifically, the contact point between the front wheel and the ground is located aft of the steering axis about which the steerer rotates. Furthermore, the trail, which is the distance along the ground, between the front wheel contact point and the steering axis is small, between approximately 0 and 75 mm. The front wheel axis and the steering axis are also aft of the centerline of the steerer.
Additional aspects of the invention include a collapsing steerer, a parallel-rail support structure, and a compact braking element.